Surface broach



Feb. 12, 1952 w. J. PHANEUF SURFACE BROACI-I 2 SHEETS-SHEET l Filed July e, 1949 INVENTOR.

Feb. 12, 1952 w. J. PHANEUF SURFACE BROACH Filed July e, 1949 2 SHEETS-SHEET 2 INVENTOR. Wlueosf lH/A/vfz/f Patented Feb. 12, 1952 UNITED STATES PATIENT @ori-*ics @SURFACE BiroAoH Wilrose J. Phaneuf, Hudson, ,Mass., assigner iV-to The`Laponte'Machine Tool Company, Hudson, `Mass., a corporationl of V Maine Applicationluly- 6, 1949, :Serial No. 103,238

(Cl.`.-2B-B.5.1.)

This invention ,relates `to a surface .type .or .external breach .having .multiple ,inserted cutters. Thebroaeh is preferably formed withlbothroughing :and finish-ing sections, and .is particularly adapted for cutting .grooves or .channels vo spe-v cialized crosscsection. As shown 'in 'thedrawinga .the :breach is .set .up 'for cutting 'the .so-called, Christmas tree grooves which receive `the"butts Vof the blades in ,certain ,commercial ,turbine rotors.

It is the general object of my 'invention to provide a broachhavingimproved'means for lsecuring multiple inserted cutters in assembled and cooperative .relation therein.

A further object is to provide an improved .breach cutter so `constructed that `successive Acutters .may .be repeatedly ground on thircutting .faces without changing their `assembled relation. .I .also provide improved means .for Zlock'ing an assembly of cutting units in abroach 'frame or base.

and Ycombinations of :parts which willbe herein- ,afterdescribedand more Vparticularly pointed out in the appendedclaims.

A preferred form of the "inventionis shown'in the drawings, iin which Fig. 1 is a plan View of .my ,improvedmultiple breach;

Fig. 2 is a side elevation of .the '.broach, looking .in thedirection of the arrow 2 in Fig. 1;

Figs. A3, 4 and 5 Aare .transverse 'sectional views, taken along the llines3-'3, 4 4 and"5'-5in"Fig. l2 respectively;

Fig. 6 is va side elevation of a breaching cutter;

Fig. 7 is a rear view thereo, looking in-the direction of the arrow "1 in '6;

Fig. 8 'is a sectional plan View, taken talong the line 8-8 in Fig. Y? but showing a plurality of assembled cutters;

Fig. 9 is a similar ibut enlarged section and taken along the line --Sin Fig. 7;

Fig. 10 is a perspective view of a reenforcing strip or bar;

Fig. l1 is a perspective view of a clamping bar;

Fig. 12 is a similar `view vof another clamping bar;

Fig. 13 is a perspective .view-of .a locking member;

Fig, 14. is a perspective-view of a locking wedge;

Fig. 15 is `a side elevation .ofa fragmentof a turbine rotor having -Christmas tree @type grooves vor channels -formed therein; and

Fig. 16 is a perspective view of a turbine blade adapted to be seated in a groove or channel of the type shown in Fig. 15.

My invention further .relates to .arrangements :Refer-ring `.to Figs. 1 to .5, my improved broach `comprises a substantially elongated base or ,frame 20 having a .longitudinal `channel .Zll extending lengthwise thereof, .and `having locking .recesses 21, .23, 24 and 2.5 formed .in the `uppersurIaCe thereof.

.Asshown herein, my .improved Jbroach comprises a pilot member 3.0, .a plurality .of .roughing :cutters.3.|..a plurality of .chamferingcuttersl a `plurality of vfinishing cutters 3.3, and .a topping bar for cutter 34.

A block or abutmentispermanently secured .the .leading .or .leftfhand .end of the broach Vframe or .base 20 .as viewed vin Figs. .1 .and"2.

.The pilot member .3.0 and ,a plurality of .rough- .ing cutters 3l .are inserted inthe channel 2l .be-

y.tvs/.een the 'block or abutment v35 and` a locking v.member Mseatedin .the ,locking ,recess 22.

"The locking 'member 140 is rpreferably .formed `as in Fig. 13 and Aisprovided with ya tapered groove or recess 4I on its backside which is .adapted ,to yreceive a correspondingly tapered YWedge l42 `(Fig. 14). The member 40 also has an upward projection '44 .which engages and Vreenforces `the upper parts of Ythe cuttingunits L31.

'Screws '46 (Fig. '3) .are threaded vin the side flanges of the 'base 20 and maybe turned `to shift the wedge '42.along the recess .4l in the .block 40; thus applying pressure to the assembled cutting units 3i! A'and pilot member 30 .and against 'the abutment'35. "Screws 48.extending through elonk:gated openings in the 'block 40 may "then be 'tightened to hdld the block 40'in adjusted position as :indicated in Fig. 4.

Thepilot member "30 'and each'of the "cutting units 31, "32 nand 33 has a shank :50 (Figs. 6 and 1T) adapted, to `i'lt inthe longitudinal groove or channel '2| in the `base "20, 'as shown in Fig. 5, .and each shank fiias .a notch '5l fin one side thereon adapted 'to receive 'the "beveled ledge nof a clamping bar "5:4 4(Fig. 1l)

Each lbar`54 has a lower supporting iiange 55 along its outer edge vand has convex lugs or projectingportions 5.6 von its beveled front edge. Screw'sl (Figs. 1 'and"5), extend through open .ings 58 "(Fig. "1'1) in the clamping vbar 54. .By tightening 'the screwsf'fl, each pair of cutting units .may be irmly secured Vin .the base 20 after 'being longitudinally positioned by the locking members 4 0 and wedges 42. rlhe provision of the 'bottom Iiiange .55 and convex surfaces *'Ei allows each .clampingbar to be rocked slightly in tightening same against .the Shanks 5D.. y

.In .the production .of .turbine rotors, it .is more or'less common practice to index Ythe rotor and to provide transverse slots or recesses therein by a sawing or milling operation and in advance of the broaching operation. The pilot 30 then enters these notches successively and each notch is broached to the desired nished size and cross section, it being understood that the cutters in each group are gradually increased in size toward the right in Figs. 1 and 2.

The flanging cutters 32 are provided for finishing the outer portion of each recess R (Fig.V

l) as it is broached in the edge or rim portion of the rotor T. The finishing cutters 33 then complete the broaching of the recess R, and the topping cutter 34 nishes the inner yendl portion so (Fig. of each recess R.

The topping cutter or bar 34 is preferably of such height that it does not reach to the bottom of the recess 2| but is supported on a shim 62 which may be selected to bring the operative edge of the topping bar to any desired position.

The general cross section of the cutters 3| is shown in Figs. 8 and 9 and the cross section `of the finishing cutters 33 is similar.

It will be noted that each cutter 3| or 33 is substantially recessed in its rear portion as indicated at l0 to provide chip clearance but has a narrow supporting web 1| between the recesses 10. The cutting face of each cutter 3| or 33 is also preferably given a concave surface as indil cated at 14 (Fig. 9) to facilitate the cutting operation and also to more effectively guide the' chips into the recesses 10.

'In order that the successive cutters may effectively reenforce each other, each cutter 3| or 33 is vertically grooved in its cutting face as indicated at 'I6 (Fig. 9), and `a reinforcing bar or strip 11 (Fig. l0) is inserted in each recess 16. Each bar 'Il is positioned to engage the back edge of one of the webs previously described, so that each cutter will be firmly seated against the next adjacent cutter.

The bars may be frictionally held in the grooves or recesses 16, or cross-pins 18 maybe inserted through holes 'i9 in the bars.

When it is necessary to grind the cutting face of a cutter, the bar 16 is removed during the grinding operation and is afterwards replaced,

so that the thickness of the cutting portions of the cutting units 3| or 33 may be substantially reduced but without effecting the assembled relation of the cutting units.

The long clamping bar 80 shown in Fig. 12 may be used for securing the elongated topping cutter 34, while the shorter clamping bars 54 are preferably used for securing each pair of cutters 3|, 32 or 33. Turbine blades of the type shown at B in Fig. 16 are adapted to be firmly seated'in the recesses R shown in Fig. 15.

Locking members 40 and locking wedges 42 are used in the locking recesses 23 and 24 as Well as in the recess 22, but a plain rectangular block or abutment S5 (Fig. 1) may be used in the recess 25.

It will be understood that the selection and arrangement of cutters herein shown is illustrative only and that the form and grouping of the cutters will be varied in accordance with the' cross section of the groove or recess to be produced.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. A sectional broach comprising a longitudinally extended body having a longitudinal channel therein, a plurality of cutting members mounted in and projecting above said body and having side notches therein with converging upper and lower faces, clamping barsl mounted on said body and having beveled inner edge portions engaging said cutting members in said notches to firmly seat said members, xed supporting means for the outer edge portions of said clamping bars, said clamping bars being angularly movable about their outer edge portions f to holding position, and securing means eifective to force said Aclamping bars downward and to 2. The combination in a sectional broach as set forth in claim l, in which the beveled edge portions of said clamping bars have convex lower bearing surfaces to engage the lower faces of the side notches of said cutting members.

3. A sectional broach comprising a body having alongitudinal channel, a plurality of adjacent cutting members mounted therein and each having its front cutting face substantially perpendicular to the bottom of said channel and having a longitudinal and central groove therein, and a spacing bar for each cutting member mounted in the central groove of its cutting face and positioned to engage the rear face of the next adjacent, cutting member to determine the spacing of said cutting members in said longitudinal channel and toreenforce said adjacent cutting member.

4. A sectional broach comprising a body having a longitudinal channel, a plurality of adjacent cutting members mounted therein and each having its front cutting face substantially perpendicular to the bottom of said channel and its cutting face and positioned to engage the rear edge face of the middle web of the next adjacent cutting member to determine the spacing of said cutting members in said longitudinal channel and to reenforce said adjacent cutting member.

5. A sectional broach comprising a body having a longitudinal channel and a plurality of adjacent cutting members mounted therein, each cutting member being relieved in its rear portion but retaining a middle web of full thickness, the front cutting face of each cutting member being concave in horizontal section, each cutting member having a transverse, central groove in its front cutting face, and a spacing bar mounted in said vgroove in said cutting member and aligned with the middle web of the next adjacent cutting member and positionedto engage said web at its rear face.

WILROSE J. PHANEUF.

REFERENCES CITED .The following references are of record in the file of this patent:

'UNITED STATES PATENTS Number Name Date v 280,866 Ryan July 10, 1883 1,272,841 Oakley July 16, 1918 1,440,933 f Perkins et al Jan. 2, 1923 

